Optimization of catalytic activity of MnCoOx catalyst for NH3–SCR at low temperature by response surface method

Abstract

The effect of the preparation method on the catalytic performance and physicochemical properties of MnCoOx catalyst for selective catalytic reduction of NOx with NH3 (NH3-SCR) at low temperature was studied. MnCoOx catalysts were prepared by solvothermal, coprecipitation and direct redox reaction. The results show that the solvothermal catalyst has excellent catalytic performance in NH3-SCR. The characterization data demonstrated that the MnCoOx-1 catalyst prepared by solvothermal method showed high activity owing to its special nano-floral structure, high contents of Mn4+ and Co3+, strong surface acidity and redox properties, and strong interaction between Mn and Co. The results showed that the reaction temperature, calcination temperature and their interactions have significant effects on the NOx conversion of the catalyst. The RSM optimization results indicated the optimum preparation parameters and reaction temperature of NOx conversion over catalyst. When the Co/Mn ratio is 0.79, the calcination temperature is 332 °C and the reaction temperature is 195 °C, the NOx conversion rate reaches the maximum. The predicted value of RSM model was strongly correlated with the experimental value, and the response value within the study range could be predicted more accurately.